1. Field of the Invention
The present invention relates to a buckle including a male member and a female member. More specifically, the present invention relates to a buckle that is used for connecting or disconnecting both ends of one string member or connecting or disconnecting two string members.
2. Description of Related Art
There has been used a buckle for connecting or disconnecting both ends of one string member or connecting or disconnecting two string members.
A conventional buckle includes a plug and a socket in which the plug is inserted to be engaged. The plug includes a plug body and a pair of leg portions formed in parallel to each other on both lateral sides of the plug body. An operating portion and an engaging portion are formed in a tip end of each of the leg portions. The socket includes a socket body and an insertion hole formed on the socket body for the plug to be inserted thereto. The insertion hole is provided with: abutment portions that abut on the leg portions to elastically deform the leg portions inward; to-be-engaged portions with which the engaging portions of the leg portions are engaged; and openings from which the operating portions of the leg portions are exposed.
With the arrangement, in order to engage the plug with the socket, the leg portions of the plug are inserted to the insertion hole of the socket. The tip ends of the leg portions are inserted in the socket while being elastically deformed inward by the abutment portions of the socket. When the engaging portions of the leg portions pass through the to-be-engaged portions of the socket, the leg portions having been elastically deformed inward elastically recover, so that the engaging portions of the leg portions are engaged with the to-be-engaged portions of the socket. In this state, the operating portions of the plug are exposed to the outside from the openings of the socket.
In order to disengage the plug from the socket, the operating portions of the plug that are exposed from the openings of the socket are pushed inward so that the leg portions are elastically deformed inward. Then, the engaging portions of the leg portions are disengaged from the to-be-engaged portions of the socket. From this state, the plug is pulled out from the socket. Through the operation, the plug can be disengaged from the socket.
In such a buckle, since the leg portions of the plug are arranged to be elastically deformable inward and outward, when the leg portions are deformed outward excessively (e.g., when the leg portions of the plug are held and opened outward excessively), the leg portions might be broken.
In order to solve the problem described above, there has been proposed an arrangement of a buckle in which a center member is projected in parallel to and between a pair of leg portions (arm members) of the plug, and the arm members and the center member are connected with a holding strap (see, for instance, Document: JP-A-10-327908). With the arrangement, when the arm members are opened outward, the holding strap is stretched to restrict the arm members so as not to be opened outward further, thereby preventing breakage of the arm members.
However, in the buckle disclosed in Document, the holding strap and the plug are integrally molded from a common material and the holding strap is arranged at a position where the arm members of the plug are maximally deformed, so that operations for inserting the plug into the socket and disengaging the plug from the socket become heavy.
More specifically, when the plug is inserted in the socket or when the plug is disengaged from the socket, the arm members need to be elastically deformed inward. However, in the conventional buckle, since the holding strap is arranged between tip ends of the arm members and a tip end of the center member, the holding strap causes a large resistance force when the arm members are elastically inward, which causes the operations to be heavy.